It was almost too good (or bad) to be true: For a comically short time (i.e., less than two years), “The Morton Downey Jr. Show” burned bright as the most controversial program on late ‘80s television. Its host, a pursed-lip gargoyle who plowed through four packs a day, brought classy guests onto his skuzzy, low-rent show. There he stirred up chaos among his audience of rowdy, emasculated Jersey boys by hurling obscenities, invective and all-too-real-seeming outrage. Through his reign he drove the normally collected Ron Paul into a tizzy, recklessly inflamed the Tawana Brawley incident and swapped flirty put-downs with Gloria Allred.

Today, he’s almost forgotten — but he shouldn’t be. “Evocateur: The Morton Downey Jr. Movie” holds his work up as a predecessor to both the trash talk show detritus of the ‘90s and the easily riled hysteria of Fox News and the Tea Party. Unlike the recent Andrew Breitbart documentary, “Evocateur” is no hagiography. It’s in awe of the man’s passion if not necessarily his message, and does some digging to find the person underneath the blowhard.

Born Sean, his father was, of course, Morton Downey, known as the Irish Nightingale, one of the biggest singers of the 1930s and ‘40s. His aunt was the great Hollywood actress Joan Bennett. MDJ hated his father, but borrowed his name anyway when he tried to become a singer himself. (Happily he had enough tiny success that footage exists of him crooning a torch song in an early music film.) If the image of MDJ as a pleasant pretty boy runs hilariously up against his traditional fire-breathing sociopath image wasn’t enough, the filmmakers also drum up photos of him hanging happily with Ted Kennedy in the 1960s, a future object of his ire.

No one can stay turned-up-to-11 pissed for very long, and “Evocateur” depicts his very brief mega-fame as a kind of possession: a mid-life crisis that made him finally more famous than his father, but took him back to where he started. Lung cancer ravaged his body, and finally, this outrage machine who yelled at anyone with the tiniest bit of authority and jetted around the world while pretending to be a working class hero was reduced to pleading with people not to be a miserable nicotine addict like him. Without taking his side, “Evocateur” makes us feel genuinely terrible for him.